"We have a set of integers, the size is 1 mill. The value of

those integers can go as large as 1 trillion. So the set might look

like [1,3, 3, 100, 23, 100, 100, 89,999999, 89, 100000000, 10000000,

10000000000000, 39, 3, 23, 1,1,1,1,1,1000, 10000000000000....], now we

need to find out the individual single integer which is mostly

repeated. Say if integer 3 repeated 1000 times, no other integers have

dups as many as it does, integer 3 will be the one we are looking for."

I did a java solution using HashMap<Integer, Integer>. Now I feel auto-boxing is a growing performance drag with increasing volume. Whenever you compute hashcode on an Integer, you must box it up to a heap object. Counting up also requires unboxing and then boxing. C++ would use simple integers.

A Java solution can avoid auto-boxing completely. Build a custom HMap class with an array of buckets, each containing a pointer to a custom LList of Pair objects. Each Pair instance consists of 2 primitive integers + pointer to the "next" Pair object.

How about a sparse array?

## Sunday, May 13, 2012

### mode finder, revisited

Labels: gr8IV_Q, original_content, z_algoDataStruct

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cppSmartPtr
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cppSTL_itr
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cppTemplate
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deepUnder
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ECN
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FixedIncom
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forex
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OO_Design
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## About Me

- familyman
- New York (Time Square), NY, United States
- http://www.linkedin.com/in/tanbin

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